Folding chairs are used in virtually every location where a large number of people need to gather and sit. Such chairs are used for two primary reasons. First, they are light and easily transported. Second, because they have a folding mechanism, they can collapse into a very compact shape that makes it easy to store and stack.
Conventional folding chairs have four principal parts. Each of these parts can be seen in the folding chair 1 depicted in FIGS. 1 and 2. The first part 10 forms both the front legs 12 and the backrest 14. The second part 20 forms the rear legs 22, and the third part 30 forms the seat. The fourth part 40 is a front leg-to-back leg connection device.
When assembled, the seat 30 is pivotally connected to the first part 10 at a first pivot point 16. The first pivot point 16 can be at any height on the first part 10 but is, typically, somewhere near the midpoint of the first part 10. The seat 30 is also pivotally connected to an upper region 24 of the second part 20 at a second pivot point 26. For stability of the legs 12, 22, both the first and second parts 10, 20 can have transverse beams 18, 28. These beams 18, 28 are optional depending upon the material of the chair 1 and the weight of the user.
The connecting device 40 is provided to limit such movement between a stowed position and an open position in which the chair 1 is used for seating.
The connecting device 40 is pivotally connected to both the first part 10 and the second part 20 at third and fourth pivot points 42, 44, 42′, 44′, respectively.
In a first embodiment of the connecting device 40′ illustrated with dashed lines, the connecting device 40′ is merely a solid beam 40′. In the first embodiment, a first tie beam (formed between the respective pivoting connections of the seat 30 and the first and second parts 10, 20) and a second tie beam (formed between the two pivoting connections of the connecting device 40′), together, establish a system that limits movement of the first and second parts 10, 20. Simply put, the first and second parts 10, 20 are limited in movement between a storage position, in which the first and second parts 10, 20 are adjacent and parallel to one another (see, e.g., FIG. 2), and an open position (see, e.g., FIG. 1), in which the first and second parts 10, 20 are at an angle to one another such that the four legs 12, 22 are disposed at a distance from one another (the feet of the legs 12, 22 being disposed along an imaginary square or rectangle), the spacing of the legs 12, 22 being sufficient to support the weight of the user when the user sits upon the seat 30.
In a second configuration of the connecting device 40, also shown in FIG. 1, the connecting device 40 has two halves 46, 48 each respectively connected to one of the first and second parts 10, 20 and an intermediate pivot joint 49 connecting the halves 46, 48. When the chair 1 is collapsed, the pivoting connecting device 40 is in a fully closed position (shown in FIG. 2), in which the two halves 46, 48 form an acute angle (or scissor shape) with respect to the pivot joint 49. When the user extends the pivoting connecting device 40 into a fully open position (shown in FIG. 1), the two halves 46, 48 can be locked (for example, by transverse tabs extending out from the plane of the connecting device 40 from one or both of the halves 46, 48 and preventing the device 40 from opening past the position shown in FIG. 1). Thus, collapse/closing of the chair 1 is not permitted until the user pulls up upon the pivot joint 49. Such upward movement, if sufficiently strong, can catch the user's finger(s) in the scissor-like jaws of the two halves 46, 48, thus, exposing the user to potential injury.
The first and second parts 10, 20 are, typically, formed from circular rods or rectangular columns. Therefore, an area between the first and second parts 10, 20 presents two relatively large pinching surfaces that are not sharp enough to cut a finger(s) disposed therebetween. Instead, the force acting upon the finger is a pressing force that, in some unfortunate cases, can crush a finger disposed therebetween.
In contrast to the crushing surfaces of the parts 10, 12, a typical configuration of the connecting device 40, 40′ is a thin, rectangular cross-sectioned bar of metal 40′ (or two of such bars 46, 48). Thus, the connecting device 40 presents a relatively thinner surface area that acts, not as a crushing surface, but, rather, as a cutting surface—like the blade of a scissors. The dangers presented by the connecting device 40, 40′ are, therefore, axiomatic.
Serious disadvantages exist in the construction of a conventional folding chair 1 shown in FIGS. 1 and 2 because the two tie beam configuration presents a plurality of significant points in which a user can catch his/her finger. These points include both the crushing points—between the first and second parts 10, 20—and the cutting points—between the connecting device 40 and either one of the first and second parts 10, 20. In particular, with the second configuration of the connecting device 40, there exists a very dangerous cutting surface between the “scissors” of the two halves 46, 48. As is evident from the scissor-like construction of the halves 46, 48, if a user has placed a finger(s) between the two halves 46, 48 while closing the chair 1 to its stowed position, there is a serious risk of cutting off the user's finger(s).
Enough experience in the industry of folding chairs has shown that any cutting surfaces are to be avoided if inadvertent finger removal is to be entirely eliminated.
This danger to users is especially true when the folding chair 1 is sized for use by a child. Children typically do not have sufficient experience with using folding chairs and/or do not understand the folding chair mechanism to appreciate the finger-cutting danger and, therefore, to sufficiently avoid this danger. What is needed, therefore, is a chair that can easily fold up for convenient storage and that can be used by children with a minimum amount of pinching surfaces and with no cutting surfaces that can sever off a child's finger(s).